Glass Eyes- Alyssa

The Proper name for 'Glass Eye' is 'Ocular Prosthesis'. Its job is to replace a missing natural eye. People lose their natural eyes do to 'Ocular Melanoma'. Ocular Melanoma is the most common primary eye tumor in adults. There's around 2,000 new cases each year in the United States. Ocular Melanoma is found in the Uvea, the Uvea is made up of the iris, the ciliary body, and the choroid.An ocular prosthetic does not provide vision. Someone with an ocular prosthetic is totally blind on the affected side and has one sided vision which affects depth perception.
The earliest known evidence of the use of a glass eye is a woman found in Shahr-I Sokhta, Iran around the years of 2900–2800 BCE. Roman and Egyptian priests are known to have produced artificial eyes as early as the fifth century BCE. They constructed them from painted clay attached to cloth and worn outside the socket. The first in-socket artificial eyes were made of gold with colored enamel, later evolving into the use of glass.

This topic relates to optics because if a person loses an eye a glass eye can replace it. Making a person have one sided vision.
http://en.wikipedia.org/wiki/Glass_eye